1. Field of the Invention
The present invention relates to safety apparatus for cushioning the body of the occupant of a vehicle to reduce the extent and severity of injuries suffered during side or oblique impact crashes. More specifically, it relates to a system of components that inflate to protect and/or cushion the torso from direct impact with the interior vehicle side structure, and to restrict the lateral motion of a vehicle occupant.
2. Background of the Invention
Side or lateral impacts are a significant cause of injuries and fatalities in automotive crashes. According to the Insurance Institute for Highway Safety (IIHS), 30 percent of all automobile occupant fatalities in the United States in 1989 involved side impact crashes.
Occupants killed in side impact crashes typically have a high incidence of torso injuries. Side impact crashes also cause severe injuries to other body regions including the head, neck, abdomen, pelvis and extremities.
FIG. 1 summarizes the distribution of injuries by body region, based on an IIHS study of 91 struck-side and 49 opposite-side fatalities in the United Kingdom in 1985. "Struck-side" refers to occupants seated on the side of the vehicle that was struck, while "opposite-side" refers to occupants who were seated on the side that was not struck. FIG. 1 shows the distribution of injuries having a severity greater than or equal to three on the Abbreviated Injury Scale (AIS) by body region for fatalities in struck-side and opposite-side crashes. According the IIHS study, 85% of struck-side occupants suffered chest injuries; 59% suffered abdomen injuries; 26% suffered pelvis injuries; 64% suffered head injuries; 12% suffered neck injuries; and 2% suffered injuries to their upper limbs and 21% to their lower limbs. FIG. 1 also shows that 73% of opposite-side occupants suffered chest injuries; 49% suffered abdomen injuries; 14% suffered pelvis injuries; 82% suffered head injuries; 20% suffered neck injuries; and 10% suffered injuries to their upper limbs and 12% to their lower limbs. The injury statistics for the struck-side and opposite-side occupants total in excess of 100% because crash victims frequently suffer from multiple injuries.
Conventional automotive safety belts and air bag systems offer inadequate torso protection in side impact crashes. These systems are generally designed to protect occupants from primary injuries sustained only in frontal impacts, or in oblique impacts up to approximately +/-30 degrees (as measured with respect to the centerline of the struck vehicle).
Federal Motor Vehicle Safety Standard "FMVSS" 214 currently defines the test procedures and performance requirements for occupant protection in side impact crashes, The dynamic requirements of FMVSS 214 have been implemented based on an escalating percentage of each manufacturer's annual production.
In response to FMVSS 214, several developments in side impact countermeasures have occurred. These countermeasures primarily include the reinforcement of side components and door structures with improved door beams, modified pillars, and improved energy-absorbing padding.
Most of these developments in response to FMVSS 214 focus on limiting the intrusion of an object into the passenger compartment. Additionally, energy-absorbing padding helps distribute the impact force to the struck-side occupant over a larger surface area. An excellent production example of these technologies is the side impact protection system incorporated into current Volvo automobiles which carries door beam loads through the front seats into the center tunnel structure.
Currently, side-impact air bag countermeasures are also being considered by several vehicle manufactures, such as Audi and General Motors. These air bags generally deploy from the door panel to provide protection for the thorax, abdomen, and pelvic regions. Volvo has disclosed a side-impact air bag that is intended for torso protection. It is housed in the seat back and is described as "about the size of a large loaf of bread." Volvo's air bag inflates when the door panel crashes into a sensing device located approximately 4 inches away from the seat structure.
These side-impact air bag systems suffer from a series of drawbacks. First, they only offer impact protection for the side of the occupant that is closest to the door. Second, side-impact air bags that deploy in the direction of the occupant may in some cases cause injuries. For example, if an occupant is leaning against the door when the air bag is triggered, he or she may suffer back, side, or kidney injuries caused by the air bag expanding against the torso, Thirds these side-impact air bag systems generally do not provide impact protection from subsequent impacts that may occur after the initial impact because they quickly deflate. Fourths they offer no means to stabilize the lateral motion of the torso, and so do not prevent or protect the occupant from injuries that may result from the recoil of the body after the initial impact. Fifth, the gas generators of these systems are generally placed in inaccessible locations (i.e. within the seat cushion or door frame) for maintenance purposes.
In light of these drawbacks, an improved side-impact torso protection system should ideally prevent or cushion the torso from directly colliding with the interior side components of a vehicle, provide continuous impact protection for possible additional side impacts during an accident, and restrain the body from substantial lateral body movement.